.calculator {
    width: 300px;
    border: 1px solid black;
    padding: 10px;
}

.display {
    width: 100%;
    height: 50px;
    background-color: lightgray;
    margin-bottom: 10px;
}

input[type="text"] {
    width: 100%;
    height: 100%;
    text-align: right;
    font-size: 24px;
}

.buttons button {
    width: 50px;
    height: 50px;
    margin: 2px;
    font-size: 20px;
}